Many RF receivers today, such as pagers, operate in multi-area systems which allow a user to pass from one area to another area while using the same receiver. These areas each have their own unique RF channels, and each channel has a unique address and telephone number assigned to each user. Therefore, as a user passes from one area into another area of a multi-area system, the receiver must begin receiving the new channel associated with the new area. The telephone number addressing the receiver may change in the new area and the address for the user in the protocol for the new RF channel will be different from that of the old RF channel address. Most often, a change in area and telephone number will mean a change in the telephone area code.
Receivers for multi-area systems are designed to show a given code indicating which area the receiver is operating in. Generally, the code and the frequency of the receiver are changed manually when the user moves from one area of operation to another. The user may have difficulty remembering which code displayed by the receiver corresponds to which area. What is preferred, then, is to have a receiver that will recognize when a new channel is selected (and corresponding area entered) and automatically signal the user using a code easily understood by the user.